Unmanned dispensers that dispense fluids, foods and other materials can be subject to contamination and tampering. For example, but not by way of limitation, unmanned fluid dispensers, such as water dispensing systems, can be contaminated by users that place their own water containers against the dispensing nozzle and transmit the contamination to other users who place containers against the same nozzle. Further, users may tamper with dispensing nozzles by placing objects in the dispensing nozzle to block the flow of the water. These objects may also contaminate the water source. Of course, this can occur in any type of fluid dispensing device, such as soft drink dispensers, milk dispensers, frozen drink dispensers, etc. Further, food dispensers, such as cereal dispensers, trail mix dispensers, bulk food dispensers, etc., where the public has direct access to these dispensers, are subject to the same problems.